Breaking a promise is generally taken to involve committing a certain kind of moral wrong, but what (if anything) explains this wrong? According to one influential theory that has been championed most recently by T.M. Scanlon, the wrong involved in breaking a promise is a matter of violating an obligation that one incurs to a promisee in virtue of giving her assurance that one will perform or refrain from performing certain acts. In this paper, we argue that the “Assurance View”, as we call it, is susceptible to two kinds of counterexamples. The first show that giving assurance is not sufficient for incurring the kind of obligation of fulfillment that one violates in breaking a promise. The second show that giving assurance is not necessary. Having shown that the Assurance View fails in these ways, we then very briefly sketch the outline of what we take to be a better view—a view that we claim is not only attractive in its own right and that avoids the earlier counterexamples, but that also affords us a deeper explanation of why the Assurance View seems initially plausible, yet nonetheless turns out to be ultimately inadequate.